Various machines are used to produce portions in a portion control apparatus. In some of these portion control machines, sheet-form paper is used for separating the portions. These sheets are often dispensed from a paper feed system, which feeds the bottom-most sheet of paper from a vertical stack of individual sheets.
One type of portion control machine forms patties of material, such as ground meat. Originally, the patties were formed by hand but this involves human contact, which can involve unsanitary conditions, as well as a lack of uniformity in the weight, size and shape of the patties, and limitations on worker output.
Portion control machines for forming patties can overcame many of these short comings by producing patties in a sanitary manner that are substantially uniform in size, shape, and weight and can also result in a significant increase in per worker output.
A patty making machine typically includes a mechanism to dispense sheets of paper to be contacted with the patty to ensure separation of the patty from other patties or surfaces. These sheets prevent “sticking” between patties or portions thereof. The most commonly used type of sheet is made of paper coated with wax. Some dispensing mechanisms use rolls of paper that are cut or torn to a desired length. However, these rolls must be continuously replaced, which results in shut-down time for the patty making machine and interruption of the patty making process.
Other paper dispensing mechanisms utilize precut sheets of paper that have one or more holes in the paper. These sheets are stacked with the holes aligned and fitting over rods or pins from which the paper is torn during dispensing. However, requiring the rods to be threaded through the holes increases the difficulty in loading the paper. Further, cutting or tearing the paper can result in small fragments of paper being deposited upon the patty. The disadvantages associated with precut sheets of paper having holes to facilitate stacking the sheets has led to the use of a system wherein the sheets are provided with deformable elements, such as notches in the side edges of the sheets.
U.S. Pat. No. 5,137,172 shows a paper feed system suitable for use with a patty making machine to provide paper for separating the patties. A vertical stack of sheet-form paper is provided with a deformable element, such as a notch, on the side edge or edges. A paper hopper is adapted to receive and temporarily retail the stack of paper sheets and is adapted to dispense the sheets by feeding the bottom-most sheet of paper from the stack. A male guide associated with the inside surface of the paper hopper engages the deformable element on the side edge of the sheets. A proximal end of the male guide adjacent to where the paper is dispensed temporarily retains the paper sheets in such a manner that the bottom-most sheet is dispensed without tearing the paper. Essentially, the deformable elements, such as the notches, on the side edges of the sheets cause each individual sheet to be bent at an extreme angle when pulled past the male guide without tearing the paper.
Normally, the frictional force between the bottom-most sheet that is being dispensed and the next sheet in the stack is insufficient to pull the next sheet free from the guide, as it is not sufficient to overcome the “hold back” force resulting from the extreme bend required to free the paper from the guide. Accordingly, the next sheet is maintained within the paper hopper by its deformable element, and thus the paper should be dispensed only a single sheet at a time.
However, this required that the sheets be sufficiently stiff to provide adequate “hold back” force necessary to allow only a bottommost sheet to be pulled away. Nonetheless, problems still have been encountered with certain sheet-form paper stock wherein there still is a tendency to pull two sheets of paper at a time if the paper feed system is not adjusted properly. Adding a more severe bend to the deformed or notched paper to increase its “hold back” force might be considered a solution to this problem, but it has been found that there is a tendency to tear the paper if it must be deformed too severely.
Another problem with previous paper feed systems is that thinner sheets have a tendency to bow downwardly and fall out of the support means of the system. The feed mechanisms used to depose the separating sheets between the patties or portions require that the sheet be supported under two of its opposite edges. Specifically, the sheets are fed along a support means which normally includes a pair of side rails which support the two opposite side edge areas of the sheets. While supported, a patty or portion is deposited on top of a sheet which is then accelerated downward to the top of a stack below. Repeated positioning of additional sheets and subsequent depositing of the portions forms a stack of interleafed patties
Previously, thinner sheets, on the order of 0.002 inches thick could not be used because they had a tendency to fall down between the side support rails due to their own weight, even before a portion is deposited on the sheet. Therefore, “stiffer” interleaf sheets which would remain in position and did not fall out of the support rails during stacking were used.
An alternative solution was to provide a means for stiffening the sheets so that they do not fall through the support means, particularly providing a sheet without adding significant cost. In addition, the stiffening means can be used to reinforce deformable elements or notches at the side edges of the sheets to increase the “hold back” forces necessary to allow a bottommost sheet to be pulled away from the next sheet in a stack thereof.
However, these notches only provided improved support at the front and back portions of the sheet and did not provide improved support at the sides. As the paper was pulled forward, the paper would sag at the center and pull away from the sides, limiting the through put of the patty portion control machine and requiring the use of thicker, less flexible sheets.
Therefore, there remains a need for improved sheet-form paper that allows for thinner sheets without the inherent problems discussed above encountered when decreasing the thickness of the sheets.